1. Field of the Invention
The present invention relates to a surface mounted capacitor, and more particularly to a surface mounted capacitor that is automatically manufactured by a surface mounting technique.
2. Description of the Related Art
Taiwan Utility Model Publication No. 266300 issued on Dec. 03, 1995 and entitled "SURFACE INSERT TYPE CHIP CAPACITOR", as shown in FIG. 1 of the drawings, discloses a surface mounted capacitor comprising a casing 10, a dielectric medium 20, a layer of rubber 30, and a support base 40. The casing 10 is made of metal and covered by an insulating film. The dielectric medium 20 includes a charged layer 21, an insulating layer 22, and two leads 23. The dielectric medium 20 is mounted inside the casing 10 and rubber 30 is provided to seal the dielectric medium 20 inside the casing 10 after filling of electrolyte. The casing 10 is rolled at a portion thereof so as to be stuck into the rubber 30 to form an annular groove 11 for preventing the rubber 30 from moving out of the casing 10. The support base 40 is mounted to an opening of the casing 10 with the leads 23 extended through the rubber 30 and then rested on an outer surface of the support base 40 after bending. Nevertheless, the casing 10 is made of metal such that the length of the insulating layer 22 must be longer than that of the charged layer 21 so as to avoid short circuit resulting from contact between the charged layer 21 of the dielectric medium 20 and the casing 10. In addition, the support base 40 is necessary for fixing the leads 23, which increases the overall length and volume of the capacitor. Further, the capacitance of the dielectric medium will be conducted outside and thus cannot be stored if the insulating film on the outer surface of the casing 10 is damaged. The good production rate for the capacitors is thus lowered. Further, the electrolyte in the casing 10 is kept inside the casing 10 by means of sealing between the annular groove and the rubber 30. Leaking of the electrolyte is likely to occur due to improper rolling or fatigue of the rubber. The good production rate is thus poor.
FIGS. 2 and 3 illustrate another conventional surface mounted capacitor that includes a casing 50, a dielectric medium 60, a layer of glue 70, and a cover 80. The casing 50 includes a lateral side 51, a first end face 52, and a second end face 53. The second end face 53 includes an opening 54. The dielectric medium 60 is firstly mounted into the casing 50 and a stop plate 55 is then provided to enclose the dielectric medium 60. The glue 70 is applied to the first end face 52 and fills the casing 50 in a manner shown in FIG. 3. Two leads 61 of the dielectric medium 60 extend out of the stop plate 55 and the glue 70 and then rest on the lateral surface 51 of the casing 50 after bending along the first end face 52. The electrolyte is filled into the casing 50 via the opening 54, and the cover 80 is then provided to seal the casing 50. Alternatively, the material around the opening 54 may be heated and thus seal the opening 54 by means of using a high-temperature die.
Nevertheless, during filling of the glue, a recessed area is formed in the first end face 52 of the casing 50 after hardening of the glue 70 due to surface tension. As a result, the portions of the leads 61 along the first end face 52 are not planar and thus not suitable to surface mounting technique (SMT). Further, a protruded section is formed on the second end face 53 of the casing 50 after mounting of the cover 80 or sealing by means of fusion. This is not suitable to a suction/holding mechanism used in SMT. As a result, the capacitor is only useable in the portion of the leads 61 along the lateral side 51 of the casing 50, and the suction/holding mechanism used in SMT can only hold the planar portion along the lateral side 51 of the casing 50. Application of the capacitor is thus limited.